Typewriting machine



Sept. l0, 1940. r w. A. DoasoN TYPEWRITING NACHMNE Filed March 31, 1939 3 Sheets-Sheet l l N VE N TO R Ma/m M550/v l ATTORNEY Sept. 10, 1940. w A, DQBS'QN 2,214,076

TYPEWRITING Imm-lima Filed March 5l, 1939 3 Sheets-Sheet 2 ATTORN EY sept 10, 1940. w. A. DoBsoN 2,214,076

TYPEWRI'TING MACHINE Filed March 5l, 1939 3 Sheets-*Sheet 3 ATTO R N EY Patented Sept. l0, 1940 UNITED STATES PATENT OFFICE TYPEWRITING MACHINE Application March 31, 1939, Serial No. 265,074

8 Claims.

This invention relates to typewriting machines and more particularly to the type actions thereof and the means for actuatingthe letter-feed or ribbon-vibrator mechanisms of the machine.

In typewriters of the general class to which this invention pertains, the type action system usually presents a series of type bars arranged, in quiescent position, in an arcuate array with the type bars inclined upwardly and forwardly from their pivots on a segment disposed so that the type bar heads at rest present a shallow arc and, when actuated, strike the platen in a downward and rearward direction. This arrangement requires a greater angle of travel for the outer type bars, the increase being gradual from the center type actions outward. The key levers are usually all pivoted on a straight fulcrum axis disposed transversely of the machine, and-the keys thereof are arranged in different banks, forming the keyboard. The keys of the different banks each having a uniform dip and the key levers of the different key banks, therefore, assume various angular movements in accordance with the diiierent key lever lengths. The different arcs of swing of the various type bars and the different key lever angular movements for the various key banks are each accommodated by the operative connections between the type bars and their key levers, which may embody a series of sub-levers, each actuated by a corresponding key lever to impart motion to a type bar. The compensating effect is had at the operative connection between the key lever and sub-lever,` which causes veach sub-lever to assume a different anguiar movement. The letter-feed or ribbon vibrator mechanism may be actuated uniformly by these sub-levers, the actuating means including a universal bar actuatable by each of the sublevers. The operation of these. mechanisms requires substantial uniformity of stroke when actuated by any type action, which necessitates that the universal bar actuating the mechanism be moved through. a substantially constant arc by each type action.

An object `of this invention is to provide, in a typewriting machine having a letter-feed mechanism, a ribbon vibrator mechanism and a straight universal bar for actuating one or both of these mechanisms, a type action system adapted to actuate the universal bar in substantially unvarying strokes, and yet afford uniformity of a substantial number of the type action elements, to thereby eiiect appreciable economies in the manufacture of the typewriter.

Another object is to provide, in a typewriter including key levers and type bars arranged substantially as above indicated and a straight universal `bar for actuating letter-feed or ribbonvibrator mechanisms, 'operative connections including sub-levers between the key levers and type bars, so arranged as to compensate for the different angles of movement of the type action members and to impart a constant stroke to the straight universal bar in actuation of one or both of these mechanisms when engaged by any of the sub-levers, notwithstanding the different angular movements of the sub-levers.

This invention further provides certain improvements in typewriting machines over those disclosed in myco-pending application Serial No. 94,329, filed August 5, i936, in which is disclosed a somewhat similar type action system to that herein set forth.

In accordance with the invention, it is desirable to employ a universal bar for actuating the letter-feed or ribbon vibrator mechanisms, which bar, for economy in manufacture and simplicity of structure, presents a straight bar of substantially uniform section throughout its length. This universal bar may be arranged adjacent the transverse row of sub-levers, each of which may include a part or nger engageable with the universal bar to actuate the associated mechanism. The sub-levers may be actuated through dinerent angular movements in accordance with the arc of swing of the corresponding type bars, by their operative connection with the keylevers, embodying preferably pin-and-cam devices; the relation of the pin and cam, and the cam shapes being so varied as to compensate forthe different angles of stroke, both of the type bars and the key levers. The various sub-levers, therefore, assume different angular movements varying substantially in accordance with the stroke of the corresponding type bar, In order that the universal bar be moved ina substantially constant angle by each type action, the pin-andcam relations are further varied so that the sublever ngers engageable with the universal bar have their bar-engaging portions disposed in an arcuate array, the distance from the straight universal bar to each of these sub-'lever finger portions increasing from a minimum at the center type actions to a maximum at the outerkmost type actions, which in eiect causes the straight universal bar and, correspondingly, the associated mechanisms, to be actuated in a substantially constant stroke by any type action.

Other objects and advantages will hereinafter appear.

In the accompanying drawings:

Figure l is a sectional View of the typewriter embodying the invention, taken on a fore-andaft medial plane of the typewriter.

Figure 2 is a View similar to Figure 1 but showing one of the type actions in actuated condition.

Figure 3 is a detail front elevational view of the letter-feed escapement mechanism shown in Figure 1.

Figure 4 is a fragmentary plan View of the typewriter as shown in Figure 1, but omitting certain of the elements therefrom for clarity.

Figures 5, 6, 7 and 8 are fragmentary side elevational views each partly illustrating a type action typical of each key bank of the keyboard, and showing for comparison a sub-lever of a medial and an outer type action, the latter being shown in phantom, and

Figure 9 is a perspective View illustrating four arrangements of the sub-levers and the pin-andcam devices for actuating same, typical of the type actions corresponding to each of the four key banks.

Referring to the drawings for a detailed description of the invention, each type action includes the conventional arrangement of type bars I2, each pivoted on a common pivot rod I3 in a type bar segment I5 inclined forwardly and downwardly from the platen I6 so that the type bar heads I1 strike the platen in a downward and rearward direction. The pivot rod I3 is arcuate and the type bars at rest accordingly present an arcuate array with each type bar inclining forwardly and upwardly from the pivot I3 and lying against a type bar rest I8, also arcuate in form. The radius of the type bar rest is somewhat greater than that of the pivot rod I3 and so, the quiescent type bar heads present a relatively shallow arc, with the outer type bars at greater angles from the segment I5, in the well known manner, to minimize the overall height of the machine and provide ample clearance for the type-bar heads at rest.

A series of key levers 20 are all fulcrumed on a straight transverse pivot rod 2l carried in a cross bar 22 providing guide slots for each of the key levers. A second cross bar 23 is arranged above the series of key levers adjacent the heads of the central type bars at rest and carries a comb 24 guiding the key levers at their intermediate portions and limiting the upward swing of same; a suitable bottoming device, not shown, being provided to limit the downward swing of the key levers. Each key lever 20 is provided with an operating key 25, all forming a keyboard in which the keys are arranged in first, second, third and fourth descending banks or transverse rows; the key levers of the different banks being therefore of various lengths. The mentioned bottoming device is so arranged that each key 25 is depressed an equal extent, that is, all of the keys have uniform dip, and the key levers 20 of the different key banks therefore assume different angular movements.

Each type bar I2 is actuated by depression of a corresponding key lever 20 through the medium of a sub-lever 21. All of these sub-levers are pivoted on a common transverse pivot rod 28 carried in the cross bar 23 and are pendent therefrom in a transverse row. Each sub-lever 21 includes an arm, 3D connected by a pull link 3| to `a drive arm 32 of each type bar I2. Each sub-lever 21 is actuated by a pin-and-cam device, each key lever carrying a pin 34 cooperating with a cam 35 on a corresponding sub-lever 21 in a manner hereinafter described. Each key lever 2i! and the corresponding sublever 21 are restored to normal quiescent position by a restoring spring 31 having its respective ends engaging the arm 3@ of the sub-lever 21 and an arm 33 projecting from each key lever adjacent the fulcrum axisthereof.

To permit the use of uniform springs 31 throughout the type action system and nevertheless assure uniform resistance to touch for the keys of any key bank notwithstanding the difference in key lever lengths, the arms 38 of the key levers of each bank have their lengths varied, substantially in accordance with the various key lever lengths, see Figure 5 to 8, inclusive.

Although, in some respects, the cams 35 and their pins 3d have a somewhat similar relation to each other in the present invention, as that shown in my copending application Serial No. 94,329, a detail description will be had to further set forth the cam and pin relations by which other compensating effects essential to the present organization are afforded. The cam 35 is formed preferably on the rear edge of the sublever 21 and includes an arcuate upper portion which, as it continues downward, blends into a downwardly and rearwardly inclined portion in which the cam curve is gradually flattened out. This formation of the cam 35, in cooperation with the pin 311i, produces the desirable effect of imparting substantial force to the' sublever at the initial depression of a key, to overcome the static inertia of the type bar at rest, which force is somewhat diminished as the type bar swings further toward the platen. The inclined, flattened form of the lower cam portion permits a greater tolerance or variation in the manufacture of the parts, so that the parts may be made with a lesser degree of accuracy and thus substantially reduce costs.

It will be observed by reference to Figures 5 to 9, inclusive, that the sub-levers 21 may be segregated into four` general groups in accordance with the different key banks to which each group of sub-levers is associated; the difference in each sub-lever group being mainly in the location of the cam 35 on the sub-lever. This difference in the cams of each group compensates mainly for the different angular movement of the key levers of the different key banks. It will be noted that the sub-levers of the group associated with the first bank of keys, Figure 5, require a lesser degree of cam-andpin action because of the greater angular movement of the associated key levers. Inversely, the group of sub-levers associated with the fourth bank of keys, Figure 8, require a greater degree of cam-and-pin action in order to compensate for the lesser angular movement of the associated key levers. The same principle of operation applies in like manner to the respective sub-levers of the second and third key banks, shown respectively in Figures 6 and 7. As shown more clearly in Figure 9, this different action of the cams of each group is produced mainly by allocating each cam differently relatively to the sub-lever pivot 28; the sublever cams for the first key bank being relatively distant from the pivot, and the cams of the second, third and fourth key banks being each progressively nearer the pivot 28.

The key levers of each key bank are distributed across the entire type action system in the conventional manner and therefore operate type bars Whose angles of stroke differ substantially from each other, as will be seen in Figure 4, wherein the key levers of the first key bank, for example, operate the fourth, eighth, twelfth, etc., type bars, counting from the right. It will be therefore apparent that the sub-levers of a certain group shall impart an angular movement to their corresponding type bars, the degree of angular movement `of which increases gradually, from a minimum at the central type actions, to a maximum at the outermost type actions, it being noted that the form of the cam of each group affords a range of actions adequately Wide to provide the angle of stroke required for any type bar. To produce this increase in the effective throw of the sublevers of any certain group, the cam pins 34 are differently located in an up and down direction along the cams, that is, nearer to or further from the sub-lever pivot. In other words, where a lesser angular movement is required, as for a central type bar, the pin 34v is located at a relatively high position relative to the cam, or closer to the pivot 28, while for a type action requiring a greater degree of effective throw, asfor an outer type bar, the pin 3d is disposed at a relatively low position on the cam. This will be seen in Figures to 8, inclusive, wherein the sub-lever for a type action adjacent the center of the machine is shown in full line, and a sub-lever for an outer type action is shown in dot-and-dash outline, with the respective cam pins correspondingly distinguished.

It will be apparent from the foregoing that the different locations of the cams on the various sublevers, and the different allocation of each pin 34 on its cam 35 relatively to the sub-lever pivot, compensate for both the different angular movements ofthe various key levers of the different key banks, and for the various degrees of stroke required for the different type bars l2. The relation of the pins 34 to their cams has a further compensating eifect as will be hereinafter manifest.

rlhe general operation of the letter-feed mechanism, shown in Figures 1 and 3, is well known and a brief description of same will therefore suince. The carriage supporting the platen l5 has the usual gear rackV 40 carried thereon, in mesh with a pinion gear 4I having an escapement wheel 42 rotatable therewith, each being rotatably mounted on` a stud 43 carried on a mounting plate 44. The plate 44 may be carried on a member, not shown, by which the platen carriage is swung in case shifting, and provides a pivot 45 for a rockable dog carrier 46 which includes a fixed dog l1 and a movable dog 48 reciprocable into the path ofthe teeth of escapement wheel 42. The platen carriage is actuated in line-typing movement by the usual drum` spring, not shown, this movement being controlled by the coaction of the dogs 41, 48 with the ratchet wheel teeth. The means for actuating the dog rocker 4B to effect the step-by-stepletter-feed movement of the carriage includes an arm 5| extending from the dog rocker, a link 52 extending lbetween said arm and an arm of a bell crank lever 53 pivoted at 54 on the mounting plate 44, and also includes a second link 55 connecting an arm of the bell crank 53 to an auxiliarylever 5B pivo-tally hung on the pivot rod 23 supporting the sub-levers 21.

Each sub-lever 21 of the series includes a `finger 51 having its forward edge engageable with a straight universal bar 58 disposed transversely of the machine and supported on arms 60 adjacent each side of the machine; the arms 60 being pivotally carried on a cross shaft Gl supported in the side plates of the machine, as shown more clearly in Figure 4. The auxiliary lever 55 is interposed between the universal bar 58 and the letter-feed mechanism to transmit a greater motion to the letter-feed mechanism than that afforded by the normal movement of the universal bar 53, the arm 56 having a slot 62 therein engaging the universal bar. In that the point of connection of the link 55 to the auxiliary lever 55 is at a greater distance from the lever pivot 23 than is the universal bar point of engagement on said lever, the extent of swing of the universal bar is multiplied somewhat by lever 55, to speed up the action of the letter-feed mechanism.

The universal bar 58 also actuates a conventional ribbon vibrator mechanism, not shown, to bring the inking ribbon into printing position as the type bar-head approaches the platen. For this purpose, a `link 53 connected to one of the arms Si! of the universal bar,I is operatively connected to the ribbon vibrator mechanism.

It may here be noted that the sub-levers 21 each have a different angular movement, varying substantially in accordance with the arc of swing of the associated type bar and increasing from a minimum at the center type actions, outward to a maximum at the outer type actions. However, the proper operation of the letter-feed mechanism, and the ribbon vibrator mechanism requires that a substantially constant stroke be imparted to these mechanisms by any type action. To produce this operating eiTect, notwithstanding that the universal bar 55 used is straight, the sublevers 2&1 are arranged so that the fingers 51 thereof present an arcuate array, as shown more clearly in Figure 4. That is, the sub-lever fingers 51 of the central type actions are close to the universal bar and the outwardly succeeding sublever lingers are each disposed at a slightly greater distance from the universal bar. In order to effect appreciable economies in manufacture by maintaining substantially the uniform shape of the sub-levers of each group', this arcuate arrangement of the sub-lever fingers is formed by so allocating the cam pins 34 in a generally foreand-aft direction or concentrically with the pivot 8 that each sub-lever 2l' will have its finger 51 disposed in the desired relation to the universal bar. That is, each pin 34, beginning at the central type action, and progressing outwardly in each direction, is disposed further rearwardly than the preceding pin, and the corresponding sub-lever fingers 51 consequently assume the arcuate array. This results in a different location of each sub-lever arm 30 which difference is taken up by a corresponding variation in the lengths of the links 3G connecting these arms to the type bars i2. It will be observed, however, as shown in Figure 4, that these links necessarily vary substantially one from the other to accommodate the arcuate array of the type bars, so that no increase in manufacturing costs is effected by further varying their lengths, It may be here noted that the fingers 51 are bendable on the sub-levers 21 for minor adjustment durfactory adjustment of the machine.

The use of the universal bar actuated in uniform or constant strokes by any of the type actions is not restricted to the actuation of the letter-feed or ribbon-vibrator mechanisms, but

may form part of the actuating means for any of the conventional typewriter mechanisms requiring operation incident to typing.

To accommodate the condition produced by the extreme angular disposition of certain of the outermost type bars I2, as shown in Figure 4, the drive arms 32 thereof may be disposed at slightly different angles from the body of the type bar than the type bar drive arms of a major number of the intermediate type actions. Likewise, slightly increased lengths for the sublever arms 30 of the outermost type actions may be desired to thereby provide a greater angle of stroke for the associated type bars.

To summarize, it will be seen that the sublever cams 35 are represented by four groups, one for each key bank of the keyboard, to compensate for the different angular movements of the key levers of each bank. Furthermore, the cam pins 34 are so disposed on the key levers 26 in a direction radial of the pivot 28 and along the cam surface, so as to produce different angles of stroke of the sub-levers in accordance with the variation of stroke of the corresponding type bars. Also, the cam pins 34 are allocated on their key levers 2l! in a direction concentric with the pivot 28, to so dispose the sub-lever fingers 5l, that a constant stroke is imparted to the universal bar 58 and therefore the letter-feed mechanism and the ribbon vibrator mechanism, for any one of the type actions, notwithstanding the different angles of stroke of the sub-levers.

It will be observed that this co-relation of the type action elements may be effected without any increase in the cost of manufacture, in that the key levers of each key bank and the sublevers of each group may each be made in identical forms, and the cam pins 34 may readily be allocated on the respective key levers in proper position with ease during manufacture; the links 3l of varying length being likewise adapted for economic manufacture.

It will be understood that the foregoing schedule regarding the correspondence of a certain group of sub-lever cams to the key levers, and the relation of the cam pins to the center of oscillation of the cams or sub-lever pivot, is given by way of example only, to illustrate the general arrangement, and does not necessarily imply the strict adherence to this schedule. For example, to obtain a greater angle of stroke for a sub-lever related to a key lever of the second bank of keys, particularly in an outer type action, a sub-lever normally intended for association with a third bank of keys may be used, to thereby require only a lesser radial differential allocation of the cooperating cam pin. Similarly, for a type action associated with a key lever of the third bank of keys, a sub-lever may be used, that was intended for use in that group associated with the fourth key bank.

Although in this application there is specilically described one embodiment which the invention may assume in practice, it will be understood that same is shown for the purposes of illustration, and that the invention may be modified from that herein shown and described, and may be embodied in various other forms,

, without departing from the spirit or scope of the levers pivoted on a straight fulcrum axis and operatively connected with said type bars, the angle of swing of said sub-levers varying substantially in accordance with the swing of the type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar to actuate same, and means for actuating said sub-levers by said key levers, said actuating means being varied for each type action to dispose said sub-levers at rest, with the bar-engageable parts thereof at different distances from said universal bar, to impart a constant stroke to said bar by any type action.

2. In a typewriting machine, a platen, a system of type actions including type bars pivoted to swing through varying angles to strike the platen, a series of key levers, a series of sub-levers pivoted on a straight fulcrum axis and operatively connected with said type bars, the angle of swing of said sub-levers varying substantially in accordance with the swing of type bars, a pivoted straight universal bar, each of said sublevers having a part engageable with said bar to actuate same, and pin-and-cam devices actuated by said key levers to swing said sub-levers, the position of the pins of said devices for each type action being varied to dispose said sub-levers at rest, with the bar-engageable parts thereof at different distances from said universal bar, to impart a constant stroke to said bar by any type action.

3. In a typewriting machine, a platen, a system of type bars pivotally mounted to strike the platen, the angles of swing of said type bars varying from a minimum at the center of the machine, a series of key levers, a series of sublevers pivoted on a common straight fulcrum axis and operatively connected with said type bars, the angles of swing of said sub-levers varying substantially in accordance with the swing of the associated type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar to actuate same, and means for actuating said sub-levers by said key levers, each of said actuating means being arranged to position said sub-levers at rest, with the bar-engageable parts thereof at distances from said universal bar gradually increasing from a minimum at the center of the machine, to impart constant strokes to said bar by any sub-lever.

4. In a typewriting machine, a platen, a system of type bars pivotally mounted to strike the platen, the angles of swing of said type bars varying from a minimum at the center of the machine, a series of key levers, a series of substantially uniform sub-levers pivoted on a common straight fulcrum axis and operatively connected with said type bars, the angles of swing of said sub-levers varying substantially in accordance with the swing of the associated type bars, a pivoted straight universal bar, each of said sublevers having a part engageable with said bar to actuate same, and pin-and-cam devices for actuating said sub-levers by said key levers to swing said type bars, the position of the pins of said devices being varied to dispose said sublevers at rest, with the bar-engageable parts thereof at distances from said universal bar gradually increasing from a minimum at the center of the machine, to impart constant strokes to said bar by any sub-lever.

5. In a typewriting machine, a platen, a system of type bars pivotally mounted to strike the platen, the angles of swing of said type bars varying from a minimum at the center of the machine, a series of key levers, a series of sublevers pivoted on a common stright fulcrum axis and operatively connected with said type bars, the angles of swing of said sub-levers varying substantially in accordance with the swing of the associated type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar to actuate same, a cam on eachof said sub-levers, and a pin on each of said key levers, the position of said pins being varied in a direction concentric with the sublever pivot to` dispose said sub-levers at rest, with the bar-engageable parts thereof at distances from said universal bar gradually increasing from a minimum at the center of the machine, to impart constant strokes to said bar by any sublever.

6. In a typewriting machine, a platen, a system of type bars pivotally mounted to swing through varying angles to strike the platen, a series of key levers pivoted on a common straight fulcrum axis, a series of substantially uniform sub-levers pivoted on a common stright fulcrum axis and operatively connected with said type bars, the angles of swing of said sub-levers varying in accordance with the swing of the associated type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar to actuate same, a cam on each of said sub-levers having a range adequate to impart the angle of stroke required for a certain number of said type bars, a pin on each of said key levers, the position of each pin along its cam being varied to or from the sub-lever pivot to suit the angle of stroke of the associated type bar, the position of said pin being further Varied in a direction concentric with the sub-lever pivot to dispose said sub-levers at rest, with the barengageable parts thereo-f at varying distances from the universal bar, to impart constant strokes to said bar by any sub-lever.

7. In a typewriting machine, a platen, a system of type bars pivotally mounted to strike the platen, the angles of swing of said type bars varying gradually from a minimum at the center of the machine, a series of key levers pivoted on a straight fulcrum axis, a series of sub-levers pivoted on a straight fulcrum axis, links connectingl said sub-levers with said type bars, the angles of swing of said sub-levers varying substantially in accordance with the swing of the associated type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar, a cam on each of said sub-levers, a pin on each of said key levers cooperating with a corresponding cam, the positions of all of said pins being Varied in a direction concentric with the sub-lever pivots to dispose said sub-levers at rest, with the bar-engageable parts thereof at distances from the universal bar gradually increasing from a minimum at the center of the machine, to impart constant strokes to said bar by any sub-lever.`

8. In a typewriting machine, a platen, a system of type bars pivotally mounted to strike the platen, the angles of swing of said type bars varying gradually from a minimum at the center of the machine, a series of key levers pivoted on a straight fulcrum axis, keys on said key levers, arranged in different key banks of a keyboard, a series of sub-levers pivoted on a straight fulcrum axis, links connecting said sub-levers with said type bars, the angles of swing of said sub-levers f varying substantially in accordance with the swing of the -associated type bars, a pivoted straight universal bar, each of said sub-levers having a part engageable with said bar, a cam on each of said sub-levers, a certain group of substantially uniform sub-levers, being associated with each key bank, the position of the cams of said sub-lever groups relatively to the sublever pivot being varied for the different key banks, a pin on each o-f said key levers cooperating with a corresponding cam, the position of the pins of each cam group being varied to or from the sub-lever pivot to accommodate the different angles of stroke of the associated type bars, the positions of all of said pins being further varied in a direction concentric with the sub-lever pivots to dispose said sub-levers at rest, with the bar-engageable parts thereof at distances from the universal bar gradually increasing from a minimum at the center of the machine, to impart constant strokes to said bar by any sub-lever.

WILLLIAM A. DOBSON.

CII

CERTIFICATE CE CORRECTION. Patent No. 2,211I,07 6. september 1o, 191m.

wIIIIAM A. DoBsoN.

It is hereby certified that error appears in the printed specification of'the above numbered patent requiring correction'as follows: vPage 5, first column, lines 5V and 2h., ciaims- 5 and respeetively, for stright read --straight'; and that the said Letters Patent should be read with this correction therein that the same may :ca n.f;'c rml to the record.l of the ease in the Alzfmtecit Office. v

signedV and sealed this 15th day of oetaber', A-.- D. 191m.

Henry Van Arsdale,` y (S681) Acting Commissioner of' Patents'. 

